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Main Boards => The Bowyer's Bench => Topic started by: skeaterbait on May 31, 2017, 11:43:00 AM

Title: Smooth-on curing question
Post by: skeaterbait on May 31, 2017, 11:43:00 AM
I have heard it said that realistically you don't need an oven to make a glass/laminated bow. That the epoxy will cure over time without the addition of heat. Since I have been sitting on these materials for about 2 years now anyway, maybe even 3, I have decided I have enough patience to go ahead and do it that way.

My question is, does the omission of heat for curing affect the Smooth On properties or does it end up the same either way?
Title: Re: Smooth-on curing question
Post by: Crooked Stic on May 31, 2017, 11:54:00 AM
When in doubt--------------
  web page (https://www.smooth-on.com/tb/files/EA40.pdf)
The thing I dont do is wipe the wood parts with acetone.
Title: Re: Smooth-on curing question
Post by: skeaterbait on May 31, 2017, 12:00:00 PM
Thank you, never really dawned on me to check there.
Title: Re: Smooth-on curing question
Post by: Mad Max on May 31, 2017, 12:51:00 PM
If the epoxy is 3 years old it may not be any good.

You can put it in your car in the summer if it's hot where you live.
Title: Re: Smooth-on curing question
Post by: macbow on May 31, 2017, 01:07:00 PM
I just glued up a tri-lam wood bow with epoxy.
I don't have a heat box. I still prefer some heat on it though.

I use a wire basket with a couple of 100 watt clip on lights under it. Set it on my table next to my form.
Cover the whole bow, form, and lights with a sleeping bag.
Wait 24 hours.
Title: Re: Smooth-on curing question
Post by: BMorv on May 31, 2017, 04:38:00 PM
I don't use Smooth On but from reading on their website you will get a better cure with heat.  I would do like Macbow suggest or make a simple heat box.  Here's the one I use to dry wood.  1 sheet of rigid insulation, some hvac tape, and (2) 100 watt light bulbs.  It gets to 125 degrees.  
   (http://i1160.photobucket.com/albums/q488/bmorvant1/IMG_1742_zpsr0d7mio8.jpg)
Title: Re: Smooth-on curing question
Post by: skeaterbait on May 31, 2017, 06:04:00 PM
I threw together a hot box today. I just need to get the light fixtures mounted and wired. I was surprised that, so far, I haven't had to run and buy anything for it.
Title: Re: Smooth-on curing question
Post by: Mad Max on May 31, 2017, 06:04:00 PM
Quote
Originally posted by BMorv:
I don't use Smooth On but from reading on their website you will get a better cure with heat.  I would do like Macbow suggest or make a simple heat box.  Here's the one I use to dry wood.  1 sheet of rigid insulation, some hvac tape, and (2) 100 watt light bulbs.  It gets to 125 degrees.  
    (http://i1160.photobucket.com/albums/q488/bmorvant1/IMG_1742_zpsr0d7mio8.jpg)
I did that too, when I started.
Title: Re: Smooth-on curing question
Post by: skeaterbait on May 31, 2017, 06:06:00 PM
I wondered about the age of the EA-40, not to mention that it's been through the full gambit of our MO weather swings.

Probably better to replace the epoxy than the lambs and glass.
Title: Re: Smooth-on curing question
Post by: Al Dean on May 31, 2017, 06:16:00 PM
Their web site covers their butts totally.  It is not quite that sensitive or no one would use it.  I do however use a hot box.
Title: Re: Smooth-on curing question
Post by: JamesV on May 31, 2017, 11:38:00 PM
I found a two quart unit of E40 on a back shelf that was over 5 years old. The cans had rusted and it smelled strong but it still got hard as the fresh stuff. I crossed my fingers on the first build but after that I just let it rip. Maybe a little darker than the fresh E40 but did the job.

James
Title: Re: Smooth-on curing question
Post by: die_dunkelheit on June 01, 2017, 10:23:00 AM
Epoxy doesn't usually "go bad." Normally what happens is some of the mixture may crystallize and it may look cloudy because of that. Apply a little heat to warm up the unmixed epoxy and it will dissolve those crystals and you're good to go. Be sure to let it fully cool before using or it'll set incredibly fast and probably catch on fire      :thumbsup: